Developer Reference

  • 2020.2
  • 07/15/2020
  • Public Content
Contents

?lauum

Computes the product
U
*
U
T
(
U
*
U
H
) or
L
T
*
L
(
L
H
*
L
), where
U
and
L
are upper or lower triangular matrices (blocked algorithm).

Syntax

call slauum
(
uplo
,
n
,
a
,
lda
,
info
)
call dlauum
(
uplo
,
n
,
a
,
lda
,
info
)
call clauum
(
uplo
,
n
,
a
,
lda
,
info
)
call zlauum
(
uplo
,
n
,
a
,
lda
,
info
)
Include Files
  • mkl.fi
Description
The routine
?lauum
computes the product
U
*
U
T
or
L
T
*
L
for real flavors, and
U
*
U
H
or
L
H
*
L
for complex flavors. Here the triangular factor
U
or
L
is stored in the upper or lower triangular part of the array
a
.
If
uplo
=
'U'
or
'u'
, then the upper triangle of the result is stored, overwriting the factor
U
in
A
.
If
uplo
=
'L'
or
'l'
, then the lower triangle of the result is stored, overwriting the factor
L
in
A
.
This is the blocked form of the algorithm, calling BLAS Level 3 Routines .
Input Parameters
The data types are given for the Fortran interface.
uplo
CHARACTER*1
.
Specifies whether the triangular factor stored in the array
a
is upper or lower triangular:
=
'U'
: Upper triangular
=
'L'
: Lower triangular
n
INTEGER
.
The order of the triangular factor
U
or
L
.
n
0
.
a
REAL
for
slauum
DOUBLE PRECISION
for
dlauum
COMPLEX
for
clauum
DOUBLE COMPLEX
for
zlauum
.
Array of size
(
lda
,
n
)
.
On entry, the triangular factor
U
or
L
.
lda
INTEGER
.
The leading dimension of the array
a
.
lda
max(1,
n
)
.
Output Parameters
a
On exit,
if
uplo
=
'U'
, then the upper triangle of
a
is overwritten with the upper triangle of the product
U
*
U
T
(
U
*
U